GCS expansion appliance: Fixed-removable expander

This study describes a new fixation system for removable appliances that does not require the fabrication of clasps and is specially recommended for patients whose teeth provide little or no retention. This fixation system, called GCS, uses attachments fabricated with orthodontic buttons bonded to the teeth. It provides excellent mechanical retention, and the removable appliances, in this case an expander, can be activated as if they were fixed appliances cemented or bonded to teeth. An additional advantage is that they may be removed for cleaning and repairs, if necessary. This study also describes a GCS retention appliance that fits into the attachments and fixes the appliance in a certain position, which precludes the use of clasps and may be adapted for practically all active or retentive orthodontic devices as it combines high retentive efficiency and fabrication simplicity.